A
Studies have documented that smiling is a universal and effective way to lift mood.But in the latest research on the power of the smile，researchers led by Marcus Munafo of the University of Bristol in England found that even seeing smiles on the faces of others can have a profound effect on a person's tendency toward violence or aggression—that is，as long as that person recognizes the smile as one of happiness，and not as a sneer (讥笑)．
Munafo and his colleagues conducted a series of experiments involving normal adults and highly aggressive teens referred to a youth program，either by educational authorities or the courts.About 70% of the teens already had a criminal record.
In the first experiment,40 healthy adults，aged 18—30，looked at facial expressions on the computer ranging from happy to angry with increasingly difficult ones to discern in between.Participants were asked how angry they felt and then had to rate the images as displaying either happiness or anger—there was no option for “unclear” or “unable to tell”．From these ratings，the scientists could generate a score of their preference toward happiness or anger.
Previous research found that aggressive people—including violent offenders—tend to consider even a common expression as an unfriendly one.“You looking at me？” can easily turn a simple question into a tragic fight.
Based on their original scores，half of the participants were then told by the computer that some of the unclear faces that they had rated as angry should have been scored as happy.This was intended to guide them toward judging the inbetween faces more positively.The other 20 received feedback that simply proved their first choices，creating a control group.
After this training，both groups were tested again and the group that received the biased (有偏见的)feedback shifted its ratings of unclear faces toward the happy side.Participants were also asked to rate their level of angry feelings again after completing the second round of testing.Those who were trained to consider unclear faces as happier reported feeling less angry afterward.
The researchers next focused on the 46 adolescents from the high risk youth program.These teens completed the same testing，but both the youth and the staff reported on the teens' levels of aggressive behavior before the testing started and for two weeks afterward.The teens trained to interpret unclear facial expressions more positively were significantly less aggressive two weeks later.
“The results of our experiments strongly suggest that the understanding of emotional facial expressions plays a causal role in subjective anger and aggressive behavior，” the authors conclude.
That doesn't mean that smiles alone are the answer to violence among adolescents—previous research in which antisocial youths were trained to better recognize emotions，for example，did not have any effect on their level of aggressive behavior.But this earlier study focused on improving teens' understanding of clear facial signals，not unclear ones.Since unclear signals are more likely to be misunderstood，it may be that violent behavior in some youths exists with their constant misunderstanding of angry expressions where they don't exist，which push them to aggressive responses.The findings suggest that helping young people，particularly those easy to be violent，to learn to give others the benefit of the doubt when they see what they think is a threatening face could help end the vicious (恶性的) cycle of violence.
1．The underlined word “discern” (Paragraph 3) means ________.
A．display obviously B．identify clearly
C．describe correctly D．value properly
2．According to Munafo's research，the anger and violent behavior in some youths resulted from ________.
A．their misunderstanding of facial emotions of others
B．their lack in knowledge of emotion recognition
C．their inborn tendency toward violence or aggression
D．their experience of being offended by others on purpose
3．The method Munafo and his colleagues used in their research is ________.
A．field investigation
B．case study
C．observation and analysis
D．experiment and comparison
4．Which of the following will Munafo and his group probably agree with?
A．Just smile as much as possible.
B．Misunderstanding is the root of violence.
C．Seeing smiles can lower aggression.
D．Control our anger to avoid violence and aggression.
【答案与解析】
1．B 词义猜测题。根据文章第三段第二句中“…there was no option for ‘unclear’ or ‘unable to tell’…”可知，画线词在此处的意思应为“清晰地辨别出来”。故答案B符合文义。
2．A 推理判断题。根据文章第一段“But in the latest research on the power of the smile…that is，as long as that person recognizes the smile as one of happiness，and not as a sneer(讥笑)．”可推知，很多年轻人易怒或行为过激，有时候是因为把友善的微笑当成讥笑了。故答案A符合文义。
3．D 推理判断题。根据文章第三段第一句“In the first experiment…”和第四段第一句“Previous research found that aggressive people…”可推知，Munafo和他的同事们的这项调查使用了实验和比较的方法。故答案D符合文义。
4．C 推理判断题。根据文章第一段“But in the latest research on the power of the smile…that is，as long as that person recognizes the smile as one of happiness，and not as a sneer(讥笑)．”和下文中的实验结果可推知，微笑可以减少人们的过激行为。故答案C符合文义。
